It is known to use of bar code symbols printed on an article in many applications. One example of such use of bar code symbols includes printing a bar code symbol on a ticket, tag, or label to be read by a department store clerk using a wand containing a bar code reader. Bar code symbols on items are also read in retail stores having a checkout counter containing a generally X-shaped window under which a flying spot scanner is located. The flying spot scanner is a device in which a beam of light is generated by a laser device and is caused to move within the area of the window for the purpose of reading the bar code symbol located on an article that is moved across the window by a store clerk.
Another type of activity in which bar code symbols are now being used is the processing of mail, such as in the sorting of mail pieces by automated sorters which include bar code readers. It is also known to use bar codes in inserting devices. A fixed beam bar code scanner is a device in which a fixed beam of light is generated by a light source within the scanner for the purpose of reading the bar code symbol located on the article being scanned as the bar code symbol passes by the fixed beam of light one bar at a time. Fixed beam bar code scanners are suitable for use in a device, such as an inserter, where the bar code symbol on the article being scanned can be maintained in alignment with the beam of the fixed beam scanner. Examples of such inserters are the model 8300 series inserters available from Pitney Bowes Inc., Stamford, Connecticut. Generally, in such inserters, sheets from a stack or a continuous web, having bar code symbols thereon, are fed sequentially past a bar code scanner for processing in the inserter. The bar code symbol on each sheet is scanned to determine control information contained in the bar code symbol, for example, how many sheets are to be inserted into an envelope. Once the determination is made as to how many sheets are to be fed together, the sheets are subsequently folded and inserts from feeder stations are added to the sheets and eventually the sheets with inserts are inserted into an envelope.
Until recently, the speed of a sheet being scanned by a fixed beam scanner in an inserter was required to be relatively slow to insure that the bar code symbol was scanned accurately. In patent application Ser. No. 269,390, filed Nov. 10, 1988 and assigned to Pitney Bowes Inc., now U.S. Pat. No. 5,008,520, and incorporated herein by reference, a method and apparatus using a fixed beam scanner for reading a bar code on a moving sheet moving at a high speed is shown.
Use of fixed beam bar code scanners in an inserter has been found to have certain limitations. One limitation is that the fixed beam bar code scanner can only read bar code symbols presented in a format commonly referred to as a ladder position bar code symbol. The sheet being scanned must be positioned so that the bar code symbol passes under, or over as the case may be, the bar code scanner one bar at a time.
Some users of inserters have a need to print bar code symbols at the bottom of a document, commonly referred to as "picket fence" position bar codes. Still other inserter users may have a need to use, at different times, both ladder and picket fence position bar codes. Because fixed beam bar code scanners can only read ladder position bar codes on documents fed from a high speed feeder, documents having picket fence position bar codes must be arranged in the high speed feeder so that when the document is fed the bar code symbol can be scanned as a ladder position bar code. For inserters handling documents having picket fence position bar code symbols, extra modules or components must be added to the inserter, such as a ninety degree transport or a turner, to present the accumulated documents in a position to be folded and inserted into an envelope. The addition of such modules prevents the user from easily changing to accommodate documents having ladder position bar codes.
Another limitation in using a fixed beam bar code scanner in an inserter is that the scanner can only perform one scan of the bar code symbol. Although fixed beam scanners can now handle the scanning of sheets moving at speeds of in excess of 100 inches/second, misreads have been experienced. Because the fixed beam scanner can only make one read of the bar code symbol, it cannot reread the bar code symbol after detecting a misread caused, for example, by imperfections in the printed bar code or by paper flutter.
It is an object of the present invention to provide high speed bar code scanning on inserters which is significantly more reliable.
It is another object of the present invention to reduce or eliminate misreads of bar code symbols in an inserter.
It is further object of the present invention to be able handle sheets having picket fence or ladder positioned bar codes without having to turn the sheets or build a ninety degree transport in the inserter system.